Compositions and methods of using chondroitinase ABCI mutants

ABSTRACT

One aspect of the present invention relates to mutants of chondroitinase ABCI. Such chondroitinase ABCI mutants exhibit altered chondroitin lyase activity or increased resistance to inactivation from stressors including exposure to UV light or heat. Methods of using chondroitinase ABCI mutant enzymes are also provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. application Ser. No. 12/338,207, filed Dec. 18, 2008, now issued as U.S. Pat. No. 7,731,956, which is a divisional application of U.S. application Ser. No. 11/527,318 filed Sep. 26, 2006, now issued as U.S. Pat. No. 7,485,295 on Feb. 3, 2009, which claims priority from U.S. Application No. 60/720,628, filed Sep. 26, 2005; all applications are herein incorporated by reference in their entirety.

BACKGROUND

Proteoglycans, major constituents of the extracellular matrix, are known to be present in large amounts in glial scar tissue and to inhibit recovery following spinal cord injuries (Fawcett & Asher, 1999). Enzymes that are capable of digesting glial scar tissue are an important target for the development of spinal cord injury (SCI) therapeutics. Chondroitinase ABCI (EC 4.2.2.4; cABCI) is a bacterial enzyme that catalyzes the digestion of sulfated chondroitin and dermatan side chains of proteoglycans. This enzyme has been shown to promote functional recovery after spinal cord injury (Bradbury et al., 2002; Caggiano et al., 2005).

The spinal cord is made up of nerve fibers. Damage to the central nervous system, including the spinal cord, results in a loss of function. Depending upon the type of injury to the central nervous system, the loss of function may manifest itself in loss of sensory, motor or autonomic function or a combination thereof. Sensory functions include the ability to feel sensations, like pain. Motor functions include the ability to voluntarily move your body. Autonomic functions include involuntary body functions, for example the ability to sweat and breathe.

The most common types of spinal cord injuries (SCI) include contusions (bruising of the spinal cord) and compression injuries (caused by prolonged pressure on the spinal cord). In contusion and compression injuries, a cavity or hole often forms in the center of the spinal cord. Unlike nerve cells, or neurons of the peripheral nervous system (PNS), neurons of the central nervous system (CNS) do not regenerate after injury.

Spinal cord injury can be characterized by contusion of the neural tissue with a resultant decrease or loss of the ability of nerve tissue to properly transmit nerve impulses. The usual cause is due to an impact injury of some nature, but it may also occur during the manipulation of the spinal cord in certain surgical procedures. After a spinal cord injury in the adult mammal, the inability of axons to regenerate may lead to loss of sensation, loss of motor function and/or loss of autonomic function, as well as permanent paralysis. One reason that neurons fail to regenerate is their inability to traverse the glial scar that develops following a spinal cord injury. The injury-induced lesion will develop glial scarring, which contains extracellular matrix molecules including chondroitin sulfate proteoglycans (CSPGs). CSPGs inhibit nerve tissue growth in vitro and nerve tissue regeneration at CSPGs rich regions in vivo.

A number of molecules, and specified regions thereof, have been implicated in the ability to support the sprouting of neurites from a neuronal cell, a process also referred to as neurite outgrowth. The term neurite refers to both axon and dendrite structures. The process of sprouting neurites is essential in neural development and regeneration, especially after physical injury or disease has damaged neuronal cells. Neurites elongate profusely during development both in the central and peripheral nervous systems of all animal species. This phenomenon pertains to both axons and dendrites.

Various polypeptides, especially cell adhesion molecules (CAMs), have been known to promote neural cell growth. While early efforts in this area of research concentrated on the adhesion-promoting extracellular matrix protein fibronectin (FN), other polypeptides have also been found to promote neural growth. For example, U.S. Pat. No. 5,792,743 discloses novel polypeptides and methods for promoting neural growth in the CNS of a mammal by administering a soluble neural CAM, a fragment thereof, or a Fc-fusion product thereof. U.S. Pat. No. 6,313,265 discloses synthetic polypeptides containing the pharmacologically active regions of CAMs that can be used in promoting nerve regeneration and repair in both peripheral nerve injuries as well as lesions in the CNS. While helpful, the use of regenerative proteins alone may not be sufficient to effect repair of a damaged nervous system.

During approximately the past two decades, knowledge of cell adhesion and migration in extracellular matrices (ECMs) at the molecular level has expanded rapidly. The action of enzymes and other polypeptides which degrade components of the extracellular matrix and basement membranes may facilitate the events of neural repair by a variety of mechanisms, including the release of bound cytokines and by increasing the permeability of the matrix, thereby enhancing the mobility of mediator molecules, growth factors and chemotactic agents, as well as the cells involved in the healing process. For example, U.S. Pat. No. 5,997,863 discloses the use of glycosaminoglycans to manipulate cell proliferation and promote wound healing.

Components of the inhibitory CSPGs have been identified as the glycosaminoglycans, chondroitin sulfate (CS) and dermatan sulfate (DS). Removal of these inhibitory molecules would allow neurites to regenerate and reinnervate an area after physical injury or disease, as well as to allow for the recovery of sensory, motor and autonomic functions.

Previous studies have found that chondroitinases can lyse and degrade CSPGs including, CS and DS. One study found that chondroitinase ABC removed glycosaminoglycan (GAG) chains in and around lesioned areas of rat CNS in vivo. The degradation of GAGs promoted expression of a growth-associated protein, GAP-43, indicating an increase in the ability of treated cells to regenerate. However, this growth-associated protein is associated with regeneration in peripheral, but not central, nerve injuries.

Chondroitin sulfates (CS) are sulfated polysaccharides in linear chains of a repeated dissacharides. They range in molecular weight from about 10,000 to over 100,000 Da. Chondroitin sulfate substrates exist in different isomers designated by the appended letters A, B, and C (Hoffman et al., 1958). The repeating units are composed of uronic acid (GlcA or IdoA) and galactosamine, and are called galactosaminoglycans, and are one example of the glycosaminoglycans, typically abbreviated as GAG. Although these GAG chain species have different repeating disaccharide regions, they are covalently bound through the so-called linkage region tetrasaccharide sequence (see below) to the serine residue in the GAG attachment consensus sequence (Glu/Asp-X-Ser-Gly) of respective core proteins. Chondroitin A and C sulfates (ChS-A, ChS-C) are the most abundant GAGs and are found in cartilage, bone and heart valves. Chondroitin B (ChS-B, or, alternatively, dermatan sulfate) is expressed mostly in skin, blood vessels, and heart valves.

When chondroitinase bacterial preparations were characterized against different chondroitin sulfate (ChS) substrates, a series of distinct chondroitinases were discovered: Chondroitinase AC that degrades mostly chondroitin A (ChA) and chondroitin C (ChC) (Yamagata et al., 1968), Chondroitinase B that degrades chondroitin B (ChB) (Michelacci and Deitrich, 1976), Chondroitinase C that acts mostly on ChC (Michelacci Y M & Dietrich C P, 1976) and Chondroitinase ABC exhibits specificity against all three substrates—ChS-A, ChS-B and ChS-C (Yamagata et al., 1968, Michelacci et al., 1987).

SUMMARY OF THE INVENTION

One aspect of the present invention provides mutants of chondroitinase ABCI.

In preferred embodiments, such chondroitinase ABCI mutants exhibit enhanced activity. In other preferred embodiments, such chondroitinase ABCI mutants exhibit enhanced resistance to inactivation, including inactivation from UV or heat exposure. More preferably, the chondroitinase ABCI mutant enzymes are selected from BC6 (SEQ ID NO:1), BE7 (SEQ ID NO:2), BF4 (SEQ ID NO:3). In another preferred embodiment, the chondroitinase ABCI mutant enzymes are selected from BC9 (SEQ ID NO:4), BC7 (SEQ ID NO:5), RD4 (SEQ ID NO:6) and BE11 (SEQ ID NO: 7).

Another embodiment of the present invention is a method of designing mutants of chondroitinase ABCI having altered activity.

Other embodiments of the present invention relate to methods for promoting neurological functional recovery, including sensory, motor and autonomic function, after central nervous system (“CNS”) injury or disease.

Further embodiments relate to methods of promoting neuronal outgrowth and the use in treating spinal cord injuries and related disorders of the CNS by administering such chondroitinase ABCI mutants.

DESCRIPTION OF THE DRAWINGS

In part, other aspects, features, benefits and advantages of the embodiments of the present invention will be apparent with regard to the following description, appended claims and accompanying drawings where:

FIG. 1 is a bar graph of the chondroitin lyase activity of wild-type, not-inactivated chondroitinase ABCI (normal), wild-type, inactivated (No Enz) and chondroitinase ABCI mutant enzymes of the present invention following UV exposure.

FIG. 2 is a bar graph of the chondroitin lyase activity of wild-type, not-inactivated chondroitinase ABCI (normal), wild-type, inactivated (No Enz) and chondroitinase ABCI mutant enzymes of the present invention.

DETAILED DESCRIPTION

Before the present compositions and methods are described, it is to be understood that this invention is not limited to the particular molecules, compositions, methodologies or protocols described, as these may vary. It is also to be understood that the terminology used in the description is for the purpose of describing the particular versions or embodiments only, and is not intended to limit the scope of the present invention which will be limited only by the appended claims.

It must also be noted that as used herein and in the appended claims, the singular forms “a”, “an”, and “the” include plural reference unless the context clearly dictates otherwise. Thus, for example, reference to a “cell” is a reference to one or more cells and equivalents thereof known to those skilled in the art, and so forth. Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of embodiments of the present invention, the preferred methods, devices, and materials are now described. All publications mentioned herein are incorporated by reference. Nothing herein is to be construed as an admission that the invention is not entitled to antedate such disclosure by virtue of prior invention.

As used herein, the term “about” means plus or minus 10% of the numerical value of the number with which it is being used. Therefore, about 50% means in the range of 45%-55%.

“Administering” when used in conjunction with a therapeutic means to administer a therapeutic directly into or onto a target tissue or to administer a therapeutic to a patient whereby the therapeutic positively impacts the tissue to which it is targeted. Thus, as used herein, the term “administering”, can include, but is not limited to, providing an enzyme into the CNS or onto the target tissue; providing an enzyme systemically to a patient by, e.g., intravenous injection whereby the therapeutic reaches the target tissue; providing an enzyme in the form of the encoding sequence thereof to the target tissue (e.g., by so-called gene-therapy techniques). “Administering” a composition may be accomplished by injection, topical administration, or by either method in combination with other known techniques.

The term “animal” as used herein includes, but is not limited to, humans and non-human vertebrates such as wild, domestic and farm animals.

The term “improves” is used to convey that the present invention changes either the appearance, form, characteristics and/or the physical attributes of the target to which it is being provided, applied or administered. The change may be demonstrated by any of the following alone or in combination, including degradation of the CSPGs of the lesioned area of the spinal cord or within the CNS or restoring, in whole or in part, motor, sensory or autonomic function of the mammal.

The term “inhibiting” includes the administration of a compound of the present invention to prevent the onset of the symptoms, alleviating the symptoms, or eliminating the disease, condition or disorder.

By “pharmaceutically acceptable”, it is meant the carrier, diluent or excipient must be compatible with the other ingredients of the formulation and not deleterious to the recipient thereof.

The term “recombinant protein” refers to a polypeptide of the present invention which is produced by recombinant DNA techniques, wherein generally, DNA encoding a polypeptide is inserted into a suitable expression vector which is in turn used to transform a host cell to produce the protein. Moreover, the phrase “derived from”, with respect to a recombinant gene, is meant to include within the meaning of “recombinant protein” those proteins having an amino acid sequence of a native protein, or an amino acid sequence similar thereto which is generated by mutations including substitutions and deletions (including truncation) of a naturally occurring form of the protein.

As used herein, the term “therapeutic” means an agent utilized to treat, combat, ameliorate, prevent or improve an unwanted condition or disease of a patient. In part, embodiments of the present invention are directed to the treatment of the central nervous system, such as degradation of the CSPGs of the lesioned area of the spinal cord or within the CNS or restoration, in whole or in part, motor, sensory or autonomic function of the mammal.

The terms “therapeutically effective amount” or “effective amount”, as used herein, may be used interchangeably and refer to an amount of a therapeutic compound component of the present invention. For example, a therapeutically effective amount of a therapeutic compound is a predetermined amount calculated to achieve the desired effect, i.e., to effectively treat an injury to the central nervous system. For example, a therapeutic compound comprising a therapeutically effective amount of chondroitinase which may be purified by a method of the present invention and formulated to provide a stable, active enzyme, is sufficient to degrade the CSPGs of the lesioned area of the spinal cord or an amount sufficient to restore, in whole or in part, motor, sensory or autonomic function of the mammal and may result in a regeneration of neurons in a central nervous system, such as by promoting axonal growth into an injured area.

The terms “treat,” “treated,” or “treating” as used herein refers to both therapeutic treatment and prophylactic or preventative measures, wherein the object is to prevent or slow down (lessen) an undesired physiological condition, disorder or disease, or to obtain beneficial or desired clinical results. For the purposes of this invention, beneficial or desired clinical results include, but are not limited to, alleviation of symptoms; diminishment of the extent of the condition, disorder or disease; stabilization (i.e., not worsening) of the state of the condition, disorder or disease; delay in onset or slowing of the progression of the condition, disorder or disease; amelioration of the condition, disorder or disease state; and remission (whether partial or total), whether detectable or undetectable, or enhancement or improvement of the condition, disorder or disease. Treatment includes eliciting a clinically significant response without excessive levels of side effects. Treatment also includes prolonging survival as compared to expected survival if not receiving treatment.

The term “vector” refers to a vehicle which can transport the nucleic acid molecules. The nucleic acid molecules encoding the chondroitinase polypeptide are covalently linked to the vector nucleic acid. With this aspect of the invention, the vector can be a plasmid, single or double stranded phage, a single or double stranded RNA or DNA viral vector, or artificial chromosome, such as a BAC, PAC, YAC, OR MAC.

Chondroitinase may be obtained from a microorganism that naturally expresses a chondroitinase; for example, but not limited to, E. coli, Proteus vulgaris or from the expression of a recombinant protein in a host cell. The host cell can be a prokaryotic cell (such as E. coli) or a eukaryotic cell (such as yeast, a mammalian cell or an insect cell).

The nucleotide sequence of chondroitinase ABCI is set forth as SEQ ID NO. 8 and the amino acid sequence of chondroitinase ABCI is set forth as SEQ ID NO. 9.

One aspect of the present invention provides mutants of chondroitinase ABCI. In a preferred embodiment, the chondroitinase ABCI mutant enzymes are selected from BC6 (SEQ ID NO:1), BE7 (SEQ ID NO:2), BF4 (SEQ ID NO:3). In another preferred embodiment, the chondroitinase ABCI mutant enzymes are selected from BC9 (SEQ ID NO:4), BC7 (SEQ ID NO:5), RD4 (SEQ ID NO:6) and BE11 (SEQ ID NO: 7).

Such enzymes may be formulated into pharmaceutical compositions and formulations. Suitable stable formulations and methods of purification are set forth in co-pending PCT Application No. US2005/017464 filed May 18, 2005 entitled “Methods of Purifying Chondroitinase and Stable Formulations Thereof” herein incorporated by reference in its entirety.

One aspect of the present invention provides mutants of chondroitinase ABCI. In preferred embodiments, such chondroitinase ABCI mutants exhibit enhanced activity.

In other preferred embodiments, such chondroitinase ABCI mutants exhibit enhanced resistance to inactivation. More preferably, the chondroitinase ABCI mutant enzymes are selected from BC6 (SEQ ID NO:1), BE7 (SEQ ID NO:2), BF4 (SEQ ID NO:3). In another preferred embodiment, the chondroitinase ABCI mutant enzymes are selected from BC9 (SEQ ID NO:4), BC7 (SEQ ID NO:5), RD4 (SEQ ID NO:6) and BE11 (SEQ ID NO: 7).

Another embodiment of the present invention is a method of designing mutants of chondroitinase ABCI having altered activity. The method comprises altering the nucleotide sequence or amino acid sequence of chondroitinase ABCI, expressing the chondroitinase ABCI in a suitable vector and measuring the activity of the mutant enzyme.

In a further embodiment, a stable chondroitinase ABCI enzyme is provided. The enzyme may exhibit increased resistance to inactivation under stressed conditions, including exposure to UV light or heat. In a preferred embodiment, the enzyme exhibits increased stability compared to wild-type chondroitinase ABCI enzyme following a challenge by a stress.

A further embodiment of the present invention is a method of treating central nervous system injuries comprising administering a chondroitinase ABCI mutant enzyme. In preferred embodiments, the chondroitinase ABCI mutant enzyme is administered in a therapeutically effective amount. In a preferred embodiment, the chondroitinase ABCI mutant enzyme is selected from the group consisting of BC6 (SEQ ID NO:1), BE7 (SEQ ID NO:2), BF4 (SEQ ID NO:3), BC9 (SEQ ID NO:4), BC7 (SEQ ID NO:5), RD4 (SEQ ID NO:6) and BE11 (SEQ ID NO: 7), more preferably, the enzyme is selected from the group consisting of BC6 (SEQ ID NO:1), BE7 (SEQ ID NO:2), and BF4 (SEQ ID NO:3). Such central nervous system injuries may include, but are not limited to, spinal cord injuries.

Another embodiment of the present invention is a method promoting neuronal outgrowth comprising administering a chondroitinase ABCI mutant enzyme. In preferred embodiments, the chondroitinase ABCI mutant enzyme is administered in a therapeutically effective amount. In a preferred embodiment, the chondroitinase ABCI mutant enzyme is selected from the group consisting of BC6 (SEQ ID NO:1), BE7 (SEQ ID NO:2), BF4 (SEQ ID NO:3), BC9 (SEQ ID NO:4), BC7 (SEQ ID NO:5), RD4 (SEQ ID NO:6) and BE11 (SEQ ID NO: 7), more preferably, the enzyme is selected from the group consisting of BC6 (SEQ ID NO:1), BE7 (SEQ ID NO:2), and BF4 (SEQ ID NO:3).

Other embodiments of the present invention relate to methods for promoting neurological functional recovery after central nervous system (“CNS”) injury or disease. In preferred embodiments, the chondroitinase ABCI mutant enzyme is administered in a therapeutically effective amount. In particular, the present invention is directed to a method of utilizing chondroitinase to promote sensory, motor or autonomic neurological functional recovery following injury in or to the spinal cord. Compositions useful in this method include acceptable formulations of chondroitinase, more particularly sustained release formulations of chondroitinase. The present invention is also directed to a method of promoting neurological functional recovery after a contusion injury to the spinal cord. The most common types of spinal cord injuries (SCI) include contusions (bruising of the spinal cord) and compression injuries (caused by pressure on the spinal cord). In contusion injuries, the most common type of injury, a cavity or hole often forms in the center of the spinal cord.

The treatments of the present disclosure deliver an effective amount of the mutant or other optional therapeutic agent to the CNS or the injured site of the CNS. Such methods may include optionally administering other chondroitin sulfate proteoglycans, including, but not limited to chondroitinase ABC_(Type1), chondroitinase ABC_(Typel1), chondroitinase AC and chondroitinase B or mammalian enzymes with chondroitinase-like activity such as Hyal1, Hyal2, Hyal3, and Hyal4, preferably to the CNS, and more preferably to the lesions of the injured area of the CNS.

As is known in the art, chondroitinase polypeptides can be produced by standard biological techniques or by chemical synthesis. For example, a host cell transfected with a nucleic acid vector directing expression of a nucleotide sequence encoding the subject polypeptides can be cultured under appropriate conditions to allow expression of the peptide to occur. The chondroitinase polypeptide may be secreted and isolated and from a mixture of cells and medium containing the recombinant chondroitinase polypeptide. Aspects of the invention described herein provide purification methods wherein the chondroitinase is isolated in a pure form that is more stable and active then those methods currently used.

Alternatively, the peptide may be retained cytoplasmically by removing the signal peptide sequence from the recombinant chondroitinase gene and the cells harvested, lysed and the protein isolated by the purification methods described herein.

Chondroitinase may be administered topically, locally or systemically. Topical or local administration is preferable for greater control of application. The chondroitinases, singularly or in combination, can be mixed with an appropriate pharmaceutical carrier prior to administration. Examples of generally used pharmaceutical carriers and additives are conventional diluents, binders, lubricants, coloring agents, disintegrating agents, buffer agents, isotonizing fatty acids, isotonizing agents, preservants, anesthetics, surfactants and the like, and are known to those skilled in the art. Specifically pharmaceutical carriers that may be used are dextran, sucrose, lactose, maltose, xylose, trehalose, mannitol, xylitol, sorbitol, inositol, serum albumin, gelatin, creatinine, polyethlene glycol, non-ionic surfactants (e.g. polyoxyethylene sorbitan fatty acid esters, polyoxyethylene hardened castor oil, sucrose fatty acid esters, polyoxyethylene polyoxypropylene glycol) and similar compounds. Pharmaceutical carriers may also be used in combination, such as polyethylene glycol and/or sucrose, or polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitan monooleate (20 E. 0.) is particularly preferred.

A treatment regimen according to the invention may be carried out by a means of administering a mutant chondroitinase ABCI enzyme of the present invention. The treatment regiment may further comprise administering chondroitinase ABCII, chondroitinase AC and chondroitinase B or mammalian enzymes with chondroitinase-like activity such as Hyal1, Hyal2, Hyal3, Hyal4 and PH2O to the lesions of the injured area of the CNS. The mode of administration, the timing of administration and the dosage are carried out such that the functional recovery from impairment of the CNS is enhanced by the promotion of neurite outgrowth.

The effective amount of chondroitinase can be administered in a single dosage, two dosages or a plurality of dosages. Although it is to be understood that the dosage may be administered at any time, in one embodiment, the dosage is administered within 12 hours after injury, or as soon as is feasible. In another embodiment, the dosage is administered to an injured mammal in one, two or a plurality of dosages; such dosages would be dependant on the severity of the injury and the amount of CSPGs present in the glial scarring. Where a plurality of dosages is administered, they may be delivered on a daily, weekly, or bi-weekly basis. The delivery of the dosages may be by means of catheter or syringe. Alternatively, the treatment can be administered during surgery to allow direct application to the glial scar.

For example, in some aspects, the invention is directed to a pharmaceutical composition comprising a compound, as defined above, and a pharmaceutically acceptable carrier or diluent, or an effective amount of a pharmaceutical composition comprising a compound as defined above.

The compounds of the present invention can be administered in the conventional manner by any route where they are active. Administration can be systemic, topical, or oral. For example, administration can be, but is not limited to, parenteral, subcutaneous, intravenous, intramuscular, intraperitoneal, transdermal, oral, buccal, or ocular routes, or intravaginally, by inhalation, by depot injections, or by implants. Thus, modes of administration for the compounds of the present invention (either alone or in combination with other pharmaceuticals) can be, but are not limited to, sublingual, injectable (including short-acting, depot, implant and pellet forms injected subcutaneously or intramuscularly), or by use of vaginal creams, suppositories, pessaries, vaginal rings, rectal suppositories, intrauterine devices, and transdermal forms such as patches and creams.

Specific modes of administration will depend on the indication. The selection of the specific route of administration and the dose regimen is to be adjusted or titrated by the clinician according to methods known to the clinician in order to obtain the optimal clinical response. The amount of compound to be administered is that amount which is therapeutically effective. The dosage to be administered will depend on the characteristics of the subject being treated, e.g., the particular animal treated, age, weight, health, types of concurrent treatment, if any, and frequency of treatments, and can be easily determined by one of skill in the art (e.g., by the clinician).

Pharmaceutical formulations containing the compounds of the present invention and a suitable carrier can be solid dosage forms which include, but are not limited to, tablets, capsules, cachets, pellets, pills, powders and granules; topical dosage forms which include, but are not limited to, solutions, powders, fluid emulsions, fluid suspensions, semi-solids, ointments, pastes, creams, gels and jellies, and foams; and parenteral dosage forms which include, but are not limited to, solutions, suspensions, emulsions, and dry powder; comprising an effective amount of a polymer or copolymer of the present invention. It is also known in the art that the active ingredients can be contained in such formulations with pharmaceutically acceptable diluents, fillers, disintegrants, binders, lubricants, surfactants, hydrophobic vehicles, water soluble vehicles, emulsifiers, buffers, humectants, moisturizers, solubilizers, preservatives and the like. The means and methods for administration are known in the art and an artisan can refer to various pharmacologic references for guidance. For example, Modern Pharmaceutics, Banker & Rhodes, Marcel Dekker, Inc. (1979); and Goodman & Gilman's The Pharmaceutical Basis of Therapeutics, 6th Edition, MacMillan Publishing Co., New York (1980) can be consulted.

The compounds of the present invention can be formulated for parenteral administration by injection, e.g., by bolus injection or continuous infusion. The compounds can be administered by continuous infusion subcutaneously over a period of about 15 minutes to about 24 hours. Formulations for injection can be presented in unit dosage form, e.g., in ampoules or in multi-dose containers, with an added preservative. The compositions can take such forms as suspensions, solutions or emulsions in oily or aqueous vehicles, and can contain formulatory agents such as suspending, stabilizing and/or dispersing agents.

For oral administration, the compounds can be formulated readily by combining these compounds with pharmaceutically acceptable carriers well known in the art. Such carriers enable the compounds of the invention to be formulated as tablets, pills, dragees, capsules, liquids, gels, syrups, slurries, suspensions and the like, for oral ingestion by a patient to be treated. Pharmaceutical preparations for oral use can be obtained by adding a solid excipient, optionally grinding the resulting mixture, and processing the mixture of granules, after adding suitable auxiliaries, if desired, to obtain tablets or dragee cores. Suitable excipients include, but are not limited to, fillers such as sugars, including, but not limited to, lactose, sucrose, mannitol, and sorbitol; cellulose preparations such as, but not limited to, maize starch, wheat starch, rice starch, potato starch, gelatin, gum tragacanth, methyl cellulose, hydroxypropylmethyl-cellulose, sodium carboxymethylcellulose, and polyvinylpyrrolidone (PVP). If desired, disintegrating agents can be added, such as, but not limited to, the cross-linked polyvinyl pyrrolidone, agar, or alginic acid, or a salt thereof such as sodium alginate.

Dragee cores can be provided with suitable coatings. For this purpose, concentrated sugar solutions can be used, which can optionally contain gum arabic, talc, polyvinyl pyrrolidone, carbopol gel, polyethylene glycol, and/or titanium dioxide, lacquer solutions, and suitable organic solvents or solvent mixtures. Dyestuffs or pigments can be added to the tablets or dragee coatings for identification or to characterize different combinations of active compound doses.

Pharmaceutical preparations which can be used orally include, but are not limited to, push-fit capsules made of gelatin, as well as soft, sealed capsules made of gelatin and a plasticizer, such as glycerol or sorbitol. The push-fit capsules can contain the active ingredients in admixture with filler such as, e.g., lactose, binders such as, e.g., starches, and/or lubricants such as, e.g., talc or magnesium stearate and, optionally, stabilizers. In soft capsules, the active compounds can be dissolved or suspended in suitable liquids, such as fatty oils, liquid paraffin, or liquid polyethylene glycols. In addition, stabilizers can be added. All formulations for oral administration should be in dosages suitable for such administration.

For buccal administration, the compositions can take the form of, e.g., tablets or lozenges formulated in a conventional manner.

For administration by inhalation, the compounds for use according to the present invention are conveniently delivered in the form of an aerosol spray presentation from pressurized packs or a nebulizer, with the use of a suitable propellant, e.g., dichlorodifluoromethane, trichlorofluoromethane, dichlorotetrafluoroethane, carbon dioxide or other suitable gas. In the case of a pressurized aerosol the dosage unit can be determined by providing a valve to deliver a metered amount. Capsules and cartridges of, e.g., gelatin for use in an inhaler or insufflator can be formulated containing a powder mix of the compound and a suitable powder base such as lactose or starch.

The compounds of the present invention can also be formulated in rectal compositions such as suppositories or retention enemas, e.g., containing conventional suppository bases such as cocoa butter or other glycerides.

In addition to the formulations described previously, the compounds of the present invention can also be formulated as a depot preparation. Such long acting formulations can be administered by implantation (for example subcutaneously or intramuscularly) or by intramuscular injection.

Depot injections can be administered at about 1 to about 6 months or longer intervals. Thus, for example, the compounds can be formulated with suitable polymeric or hydrophobic materials (for example as an emulsion in an acceptable oil) or ion exchange resins, or as sparingly soluble derivatives, for example, as a sparingly soluble salt.

In transdermal administration, the compounds of the present invention, for example, can be applied to a plaster, or can be applied by transdermal, therapeutic systems that are consequently supplied to the organism.

Pharmaceutical compositions of the compounds also can comprise suitable solid or gel phase carriers or excipients. Examples of such carriers or excipients include but are not limited to calcium carbonate, calcium phosphate, various sugars, starches, cellulose derivatives, gelatin, and polymers such as, e.g., polyethylene glycols.

The compounds of the present invention can also be administered in combination with other active ingredients, such as, for example, adjuvants, protease inhibitors, or other compatible drugs or compounds where such combination is seen to be desirable or advantageous in achieving the desired effects of the methods described herein.

The following methods are used to illustrate the various embodiments of the present invention. The methods are exemplary methods and are not meant to limit the invention.

Example 1

The present example illustrates exemplary chondroitinase mutant enzymes of the present invention. All nucleotide and amino acids are indicated as the wild-type and then the mutant version (Wild-type to Mutant).

Amino Acid Mutant ABCI enzyme Nucleotide sequence sequence BC6 (SEQ ID NO. 1) T1206 to C1206 E403 to G403 C1114 to A1114 W372 to C372 BE7 (SEQ ID NO. 2) G1925 to T1925 S642 to I642 T2226 to G2226 I742 to M742 BF4 (SEQ ID NO. 3) T2160 to A2160 N720 to K720e BC9 (SEQ ID NO. 4) G1238 to A1238 S413 to N413 BC7 (SEQ ID NO. 5) A1468 to G1468 K490 to E490 RD4 (SEQ ID NO. 6) T1661 to A1661 L554 to H554 BE11 (SEQ ID NO. 7) A1901 to T1901 D634 to V634 C1935 to T1935 (in wobble position of codon- does not result in AA change)

Example 2

The present example illustrates the chondroitin lyase activity of exemplary chondroitinase ABCI mutants according to the present invention following UV exposure. Mutant chondroitinase ABIC genes were generated and transformed into bacteria. Bacteria were grown and the mutagenized chondroitinase expressed. The chondroitinase were then exposed to UV light and their chondroitin lyase activity measured. As depicted in FIG. 1, clone BC6 (SEQ ID NO:1), BE7 (SEQ ID NO:2) and BF4 (SEQ ID NO:3) exhibited greater chondroitin lyase activity following exposure to UV light as compared to control.

Example 3

The present example illustrates the chondroitin lyase activity of exemplary chondroitinase ABCI mutants according to the present invention. The chondroitinase lyase activity of Clone BC9, Clone BC7, Clone RD4 and Clone BE11 under normal (i.e., non-stressed) conditions was measured and exhibited decreased activity as compared to control an wild-type chondroitinase ABCI, as depicted in FIG. 2.

Although the present invention has been described in considerable detail with reference to certain preferred embodiments thereof, other versions are possible. Therefore the spirit and scope of the appended claims should not be limited to the description and the preferred versions contained within this specification. 

1. An isolated mutant chondroitinase ABCI enzyme comprising the amino acid sequence of SEQ ID NO:
 3. 2. A method of treating a central nervous system injury comprising administering a therapeutically effective amount of an isolated mutant chondroitinase ABCI enzyme comprising the amino acid sequence of SEQ ID NO:
 3. 3. The method of claim 2, wherein the enzyme is administered following a contusion injury to the central nervous system.
 4. The method of claim 2, wherein the enzyme is administered following a non-contusion injury to the central nervous system.
 5. The method of claim 2, wherein the enzyme is administered following a spinal cord injury.
 6. The method of claim 2, wherein the enzyme is administered locally.
 7. The method of claim 6, wherein the local administration is selected from intrathecal and topical administration.
 8. A method of promoting neuronal outgrowth comprising administering a therapeutically effective amount of an isolated mutant chondroitinase ABCI enzyme comprising the amino acid sequence of SEQ ID NO:
 3. 9. The method of claim 8, wherein the enzyme is administered following a contusion injury to the central nervous system.
 10. The method of claim 8, wherein the enzyme is administered following a non-contusion injury to the central nervous system.
 11. The method of claim 8, wherein the enzyme is administered following a spinal cord injury.
 12. The method of claim 8, wherein the enzyme is administered locally.
 13. The method of claim 12, wherein the local administration is selected from intrathecal and topical administration. 